1. Field of the Invention
The present invention relates to a system and method for sending and receiving job data via a communication line, and so on.
2. Description of the Related Art
A printing device located in a network sometimes receives, via a so-called print server, data for printing from a terminal located in another network to carry out printing. As such printing methods, pull printing and push printing have been proposed.
Pull printing is a printing method. According to the method, a print server receives data for printing from a terminal, and saves the same temporarily. In response to a request from a printing device, the print server transfers the data for printing to the printing device. Then, the printing device carries out printing based on the data for printing.
Push printing is also a printing method. According to the method, a print server receives data for printing from a terminal and sends the same to a printing device independent of whether or not a request is sent from the printing device. Then, the printing device carries out printing based on the data for printing.
When a terminal and a printing device are located in different networks, it is necessary to solve a problem related to private IP address. A method has been proposed in Japanese Laid-open Patent Publication No. 2007-48031. According to the method, a hosting server is provided with a terminal device information storage management means storing and holding a printer port number of a printer, a port number, and a dynamic global IP address transmitted from a terminal device. The hosting server transmits information stored therein to the terminal device on the basis of information stored in the terminal device information storage management means. The terminal device transmits information thereon to the hosting server periodically or when the need arises to update the terminal device information storage management means of the hosting server.
In the meantime, a method has been proposed for executing push printing when it cannot be performed (Japanese Laid-open Patent Publication No. 2002-189581). According to the method, after a first printer receives a first print job (push print job) from a user computer, when the execution of the first print job becomes impossible due to the occurrence of any error, the first printer searches for a pertinent second printer in order to execute the first print job from a network, and issues, to the second printer, a second print job (pull print job) newly prepared on the basis of the first print job (Japanese Laid-open Patent Publication No. 2012-189581).
According to the method described in Japanese Laid-open Patent Publication No. 2002-189581, the first printer finds that executing a job for push printing is disabled after the first printer receives the push print job. If an upstream device of the first printer has a problem, the first printer can receive no print jobs. When no problem occurs in the first printer even if the upstream device thereof has a problem, it is desired that the first printer is caused to execute a print job.